This invention relates to an improvement in devices for intermittent delivery of fluid under pressure. In a more specific embodiment, it relates to improvements in such devices for delivery of water to pools; and in its most pertinent application it relates to the use of pop-up heads to deliver water for cleaning and scrubbing purposes in swimming pools.
In the prior art, various devices have been invented for the purpose of delivering water to swimming pools for the specific purpose of scrubbing the interior walls and floors thereof, or simply to agitate the water and put the fine solids in suspension to facilitate their removal by the filtering system of the swimming pool. Such devices progressed from stationary protrusions from the walls of the swimming pool which direct a continuous stream of water in one direction only to rotary heads which deliver a constant stream of water from either stationary or pop-up heads to pop-up heads which deliver a stream of water which changes in angular direction on successive intermittent uses of the head.
An example of the fixed protruding type which introduced a steady flow of fluid into a swimming pool may be found in U.S. Pat. No. 3,045,829 to Rule. An example of a fixed protruding head that delivers water from a constantly rotating head may be found in U.S. Pat. No. 3,247,969 to Miller. An example of a head which is rotated constantly to deliver fluid jets may be found in U.S. Pat. No. 3,675,252 to Ghiz and in U.S. Pat. No. 3,770,203 to Dyar. An example in the prior art of a swimming pool head adapted to intermittent delivery of a jet of water in a general direction may be found in U.S. Pat. No. 3,506,489 to Baker and in U.S. Pat. No. 3,408,006 to Stanwood. The fundamental purposes of all of these devices is to stir up the sediment and debris deposited on the walls and floor of the swimming pool so that it may be put into suspension in the water and removed from the water by the pool filter system.
An inspection of the references cited will show that for esthetic reasons the ideal water delivery head will be of the pop-up nature which is flush with the walls of the pool when not in use and which pops up for delivery of a stream of water. Functionally, to avoid the swirl effect, ideally the stream should be ejected from the head in a straight line, and the action should be intermittent in view of limited pressure values of the pool system.
In the prior art the latter objective has been accomplished by seriatim, intermittent routing of a supply of fluid under pressure to a plurality of lines, each of which has a head at the end. This is accomplished by means of a valving arrangement that distributes water seriatim to the various lines and their associated heads.
However, there are a number of problems with the prior art devices remaining to be solved. One of the problems is the complexity of the mechanism used to advance the heads. Another problem is the susceptibility of complicated mechanisms to disablement due to small bits of sediment suspended in the water and drawn into the mechanism. Yet another problem is the difficulty of servicing the prior art devices once installed, instances of which are the necessity of servicing the heads while submerged in the swimming pool in which they are installed. Yet another problem is the increased cost which necessarily goes along with making a complex mechanical structure.